Generally, such a device usually comprises:                means for automatically and repetitively monitoring, during a flight of the aircraft, a plurality of aircraft data so as to be able to detect a low energy situation, for which conditions relating to a low energy are satisfied; and        means for automatically activating, if such a low energy situation is detected, a protection function consisting in automatically engaging an autothrust and in automatically controlling the engines of the aircraft so that they supply a maximum thrust.        
The protection function which is defined in the flight guidance and control computers of the aircraft therefore generates, in all the cases where the aircraft is in a low energy situation, an automatic increase in the thrust to reach the maximum engine thrust, and does so regardless of the initial position of the aircraft throttles.